'\" t
.\"     Title: lttng-crash
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 14 June 2021
.\"    Manual: LTTng Manual
.\"    Source: LTTng 2.13.11
.\"  Language: English
.\"
.TH "LTTNG\-CRASH" "1" "14 June 2021" "LTTng 2\&.13\&.11" "LTTng Manual"
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.SH "NAME"
lttng-crash \- Recover and read LTTng trace buffers in the event of a crash
.SH "SYNOPSIS"
.sp
.nf
\fBlttng\-crash\fR [\fB--extract\fR=\fIDIR\fR | \fB--viewer\fR=\fIREADER\fR] [\fB-verbose\fR]\&... \fISHMDIR\fR
.fi
.SH "DESCRIPTION"
.sp
The \fILinux Trace Toolkit: next generation\fR <https://lttng.org/> is an open\-source software package used for correlated tracing of the Linux kernel, user applications, and user libraries\&.
.sp
LTTng consists of Linux kernel modules (for Linux kernel tracing) and dynamically loaded libraries (for user application and library tracing)\&.
.sp
The \fBlttng-crash\fR command\-line tool recovers LTTng trace buffers in the event of a system crash\&.
.sp
\fBlttng-crash\fR reads files within the directory \fISHMDIR\fR and does one of:
.PP
Without the \fB--extract\fR option
.RS 4
Launches a trace reader (see the
\fB--viewer\fR
option) to view the recovered traces\&.
.RE
.PP
With the \fB--extract\fR=\fIDIR\fR option
.RS 4
Extracts the files as uncorrupted LTTng traces to the
\fIDIR\fR
directory\&.
.RE
.sp
\fISHMDIR\fR is the directory specified as the argument of the \fB--shm-path\fR option of the \fBlttng-create\fR(1) command used to create the recording session for which to recover the traces\&.
.SH "OPTIONS"
.PP
\fB-x\fR \fIDIR\fR, \fB--extract\fR=\fIDIR\fR
.RS 4
Extract recovered traces to the directory
\fIDIR\fR; do NOT execute any trace reader\&.
.RE
.PP
\fB-v\fR, \fB--verbose\fR
.RS 4
Increase verbosity\&.
.sp
Specify this option up to three times to get more levels of verbosity\&.
.RE
.PP
\fB-e\fR \fIREADER\fR, \fB--viewer\fR=\fIREADER\fR
.RS 4
Use the trace reader
\fIREADER\fR
to read the trace buffers\&.
.sp
\fIREADER\fR
is the absolute path to the reader command to use, and it can contain command arguments as well\&.
\fBlttng-crash\fR
passes the trace directory paths to the
\fIREADER\fR
command as its last arguments\&.
.sp
Without this option,
\fBlttng crash\fR
uses
\fBbabeltrace2\fR(1)
if it\(cqs available\&. Otherwise, it tries to use
\fBbabeltrace\fR(1)\&.
.RE
.SS "Program information"
.PP
\fB-h\fR, \fB--help\fR
.RS 4
Show help\&.
.sp
This option attempts to launch
\fB/usr/bin/man\fR
to view this manual page\&. Override the manual pager path with the
\fBLTTNG_MAN_BIN_PATH\fR
environment variable\&.
.RE
.PP
\fB--list-options\fR
.RS 4
List available command options and quit\&.
.RE
.PP
\fB-V\fR, \fB--version\fR
.RS 4
Show version and quit\&.
.RE
.SH "EXIT STATUS"
.PP
\fB0\fR
.RS 4
Success
.RE
.PP
\fB1\fR
.RS 4
Error
.RE
.PP
\fB3\fR
.RS 4
Fatal error
.RE
.SH "RESOURCES"
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LTTng project website <https://lttng.org>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LTTng documentation <https://lttng.org/docs>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LTTng bug tracker <https://bugs.lttng.org>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Git repositories <https://git.lttng.org>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
GitHub organization <https://github.com/lttng>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Continuous integration <https://ci.lttng.org/>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Mailing list <https://lists.lttng.org/>
for support and development:
\fBlttng-dev@lists.lttng.org\fR
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
IRC channel <irc://irc.oftc.net/lttng>:
\fB#lttng\fR
on
\fBirc.oftc.net\fR
.RE
.SH "COPYRIGHT"
.sp
This program is part of the LTTng\-tools project\&.
.sp
LTTng\-tools is distributed under the GNU General Public License version\ \&2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>\&. See the \fBLICENSE\fR <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file for details\&.
.SH "THANKS"
.sp
Special thanks to Michel Dagenais and the DORSAL laboratory <http://www.dorsal.polymtl.ca/> at \('Ecole Polytechnique de Montr\('eal for the LTTng journey\&.
.sp
Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases\&.
.SH "SEE ALSO"
.sp
\fBbabeltrace2\fR(1), \fBlttng\fR(1), \fBlttng-create\fR(1)